Uterine fibroids are non-cancerous tumors that develop in the wall of uterus. Such fibroids occur in a large percentage of the female population, with some studies indicating up to 40 percent of all women have fibroids. Uterine fibroids can grow over time to be several centimeters in diameter and symptoms can include menorrhagia, reproductive dysfunction, pelvic pressure and pain.
One current treatment of fibroids is hysteroscopic resection or myomectomy which involves transcervical access to the uterus with a hysteroscope together with insertion of a cutting instrument through a working channel in the hysteroscope. The cutting instrument may be a mechanical tissue cutter or an electrosurgical resection device such as a cutting loop. Mechanical cutting devices are disclosed in U.S. Pat. Nos. 7,226,459; 6,032,673 and 5,730,752 and U.S. Published Patent Appl. 2009/0270898. An electrosurgical cutting device is disclosed in U.S. Pat. No. 5,906,615.
In a myomectomy or hysteroscopic resection, the initial step of the procedure includes distention of the uterine cavity to create a working space for assisting viewing through the hysteroscope. In a relaxed state, the uterine cavity collapses with the uterine walls in contact with one another. A fluid management system is used to distend the uterus to provide a working space wherein a fluid is administered through a passageway in the hysteroscope under sufficient pressure to expand or distend the uterine cavity. The fluids used to distend the uterus are typically liquid aqueous solutions such as a saline solution or a sugar-based aqueous solution.
In some RF electrosurgical resection procedures, the distending fluid is a non-conductive aqueous solution to limit RF current conduction.
One particular concern is the fact that fluid management systems typically administer the fluid under a pressure of up to 100 mm Hg or more which results in a significant risk that the distending fluid may be taken up by a cut blood vessel exposed in the uterine cavity. Such unwanted fluid uptake is known as intravasation, which can lead to serious complications and even death. For this reason, fluid management systems have been developed to monitor the patient's fluid uptake on a continuous basis during a procedure, typically using complicated systems that capture, collect and weigh distending fluids that flow through the uterine cavity.
For these reasons, it would be desirable to provide improved fluid management systems and methods for their use for performing hysteroscopic fibroid resection, myomectomy, or other similar procedures which require fluid distension. The systems and methods preferably utilize a limited volume of distending fluid and will provide for an alarm and/or system shut down when it appears that excessive fluid has been lost from the system. At least some of these objectives will be met by the inventions described herein below.